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Lathe work on hardened material

Re:

Heat treating is more of a science than just, heat, quench...
We have quite a bit of stuff heat treated at work, sometimes they blow it, and have to draw it back down. Hell some treatments are like a 23 hour bake. Lots of info on it, shits way above my head, I just figure out what I need, write paperwork and send it to our heat treat shop.
 
That is carburizing


I had a book from a steel company that told me what to heat the type of material to, how long to hold it at that temp and what to media to quench it in. To get the desired Rockwell hardness. It can make you make pull you hair out when you have to hold a tight tolerance then heat treat it cause you can't hardly grind or machine it afterwards. I have killed some high dollar chunks of metal because of heat treating. Glad I don't mess with it anymore.

http://www.engineersedge.com/materials/quenching-review.htm
 
Me, too. But we are getting way past the point of cost vs. profit for my job now. :)
 
Make an attachment to hold a die grinder in place of your tool holder. Grinding hardened material is easier and can produce a more finished look.

I'd bet u can buy different grits of die grinding bits/stones cheaper than carbide or diamond. You will want to be able to either run water over the bit or periodically dress the wheel on a dressing stone asbit loads up with material.


Materials for said die grinder holder:
A piece of tube the die grinder can fit it
A nut and bolt 3/8-1/2"
A piece of flat stock that will fit in or somehow attach to your tool holder

Hopefully by now u get the idea... You'd basically be making your lathe into an OD grinder... Good luck
 
Gittinit said:
Make an attachment to hold a die grinder in place of your tool holder. Grinding hardened material is easier and can produce a more finished look.

I'd bet u can buy different grits of die grinding bits/stones cheaper than carbide or diamond. You will want to be able to either run water over the bit or periodically dress the wheel on a dressing stone asbit loads up with material.


Materials for said die grinder holder:
A piece of tube the die grinder can fit it
A nut and bolt 3/8-1/2"
A piece of flat stock that will fit in or somehow attach to your tool holder

Hopefully by now u get the idea... You'd basically be making your lathe into an OD grinder... Good luck
Click to expand...


You get in the high 50's or 60 Rockwell that make shift tool post grinder isn't going to cut it (pun). It will chatter and push off.


Patooyee, I turned some Yukon chromollys a few years ago they got soft and easy to turn after I got through the outer .125. Make sure you put a good radius at any steps that way you won't have any stress points.
 
I'm trying to cut on 2 things.

T-case output shafts - these are really hard on the outside and get softer inside. Still not soft though. I have more success with these than ...

CV joint bells - these mother ****ers are hard as **** through and through. Its like trying to cut concrete with a razor blade. They also don't generate chips as far as I have been able to experiment. They generate long, sharp, continuous strands no matter how much or little I try to take at a time. To cut one bell the way I wanted it took 3 HSS bits going slow as all hell.
 
patooyee said:
I'm trying to cut on 2 things.

T-case output shafts - these are really hard on the outside and get softer inside. Still not soft though. I have more success with these than ...

CV joint bells - these mother ****ers are hard as **** through and through. Its like trying to cut concrete with a razor blade. They also don't generate chips as far as I have been able to experiment. They generate long, sharp, continuous strands no matter how much or little I try to take at a time. To cut one bell the way I wanted it took 3 HSS bits going slow as all hell.
Click to expand...

Good luck, keep playing with your speeds and feeds it will come together.
 
High speed isn't going to cut that but carbide will chew that up.

I've never seen anything hard enough I could not cut it, and you can grind anything. It's all about getting the carbon to the surface, that's what makes it hard, some materials do quench but for the most part you heat them in an oven.
 
Re:

Grinding steel loads up the wheel really fast, I tried grinding a ring gear when I shaved my 14 bolt, got tired of dressing the wheel, went back to the lathe.
 
You have to have the right grinding wheels, surface grinders for instance are for grinding hard steels for the most part. And they make different types of wheels for regular hand grinders also, even make some for aluminum to keep them from loading up, not really sure what the difference in properties is in those but they work great. Carbide is terrible hard and you can still grind it with a diamond wheel on a surface grinder. Just remember you have to have a cutting tool harder than what your cutting, otherwise the only cutting your doing is thru friction, and on your lathe bits when you hand grind them you don't want them really sharp, I know that sounds wierd but if you look at carbide inserts they are not sharp at all, in trade school they teach you to slightly round a bit after you sharpen it.
 
Check out Shars tool they have cheap tooling but pretty good quality lot of good inserts and holders I to play with machine work and trust me I know how frustrating it can be trying to learn it all on your own
 
kmcminn said:
You get in the high 50's or 60 Rockwell that make shift tool post grinder isn't going to cut it (pun). It will chatter and push off.


Patooyee, I turned some Yukon chromollys a few years ago they got soft and easy to turn after I got through the outer .125. Make sure you put a good radius at any steps that way you won't have any stress points.
Click to expand...

Hardness wasn't specified... I suppose if he didn't know to use a carbide bit on hardened steel, that knowing actual Rockwell hardness of the materials being machined, was out of the question.

The long field treated ring gear I shaved for my 14 bolt was impossible to turn in the big lathe. I had to set it up on the old OD/ID grinder and take about a half thousandths per pass... That thing took me about 6 hrs to setup and grind. I doubt I wouldnt have been able to get it done in the lathe.
 
I bet a carbide end mill would have made short work of that gear, either on a Cnc mill or a conventional mill with a rotary table, don't you think it probably had more to do with it being an interrupted cut on the teeth themselves vs the hardness.
 
Re:

Another thing on cutting hardened stuff os having the right grade of carbide. The harder the material the better carbide you will need. I have a few inserts at work that are .999 carbide which is about as pure as it gets and you can cut damn near anything with them.

We do alot of carbide coating at work and it has to be cut on a grinder with a diamond wheel. It is some hard ****

Sent from my SAMSUNG-SM-G890A using Tapatalk
 
Elliott said:
I bet a carbide end mill would have made short work of that gear, either on a Cnc mill or a conventional mill with a rotary table, don't you think it probably had more to do with it being an interrupted cut on the teeth themselves vs the hardness.
Click to expand...

I'd say that is very likely. Best I could have done was a rotary table on the mill as far as doing like you suggest... Couldn't imagine cranking that rotary table that much though.

The shop I work in is setup for specific die repair so I'm limited on tools.
 

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